1. Field of the Invention
The invention relates to touch control circuits, and particularly touch control switches for use in controlling AC lighting installations having either reactive or resistive lamp loads.
2. Prior Art Statement
Touch control circuits, such as for use in controlling AC lighting installations, are well known, such as described in my previous U.S. Pat. No. 3,811,054, or in U.S. Pat. Nos. 3,666,988; 3,679,910; 3,805,096 or 3,857,100. None of these prior art control systems, with the exception of my previous U.S. Pat. No. 3,811,054, discloses a system which is essentially immune to line voltage drops in the line while also being essentially immune to external interference, is capable of operating over a wide AC voltage range without requiring a change in circuit components, and is also self-trimming so as to compensate for variations in reactance due to both touch wire length as well as variations in the body reactance of the person operating the switch. For example, U.S. Pat. Nos. 3,679,910 and 3,666,988 are both subject to the antenna effect and are not flexible in that they are dependent on a particular voltage and a particular touch wire length. With respect to my previous U.S. Pat. No. 3,811,054, although the touch control circuit disclosed therein is quite satisfactory for many purposes, such as for use with resistive lamp loads, it still requires modification for use with inductive lamp loads and has a higher non-load power dissipation than that of the present invention. Moreover, the touch control circuit of the present invention is more readily susceptible to monolithic circuit integration than my previous U.S. Pat. No. 3,811,054. In this regard, it is the entire touch control circuit which should preferably be the subject of monolithic circuit integration and not merely a component part, such as, for example, the type of conventional counter control circuitry disclosed in U.S. Pat. No. 2,851,596.
The above disadvantages of the prior art are overcome by the improvements of the present invention.